The seven continents (in order of size): Asia, Africa, North America, South America, Antarctica, Europe, and Australasia/Oceania.
The seven oceans: North Pacific, South Pacific, North Atlantic, South Atlantic, Indian Ocean, Southern Sea, Arctic Ocean
The four U.S. time zones: PST (Pacific Standard Time); MT (Mountain Time: PST plus one hour); CST (Central Standard Time: PST plus two hours); EST (Eastern Standard Time: PST plus three hours)
The five geographical zones of Earth: Arctic and antarctic (in the far north and south); north temperate and south temperate; and tropical (the middle of Earth on both sides of the equator)
Latitude lines/parallels: Imaginary lines running horizontally around the globe. They are measured in degrees, with the equator at 0° latitude, the north pole at 90° north and the south pole at 90° south.
Longitude lines/meridians: Imaginary lines running vertically around the globe. These meet at both poles. They are measured in degrees, with the prime meridian at 0° longitude (at Earth’s axis), and the farthest extensions at 180° east and 180° west.
Geographic coordinates: The two-number combination that gives a location’s latitude and longitude
Hemisphere: A hemisphere is half the Earth’s surface. The four hemispheres are the Northern and Southern hemispheres, divided by the equator (0° latitude), and the Eastern and Western hemispheres, divided by the prime meridian (0° longitude) and the International Date Line (180°).
Equator: The imaginary line around the center of the earth that we measure as zero degrees latitude. The Sun is directly overhead the equator at noon on the two equinoxes (March and Sept. 20 or 21). The equator divides the globe into the Northern and Southern hemispheres. The equator appears halfway between the North and South poles, at the widest circumference of the globe. It is 24,901.55 miles (40,075.16 km) long.
Prime Meridian: The imaginary line down the center of the earth that we measure as zero degrees longitude (0°). It runs through the Royal Greenwich Observatory in Greenwich, England and divides the globe into the Western and Eastern hemispheres. The Earth’s time zones are measured from it.
International Date Line: The imaginary line located at approximately 180° longitude that, by convention, marks the end of one calendar day and the beginning of the next. It bends around countries to avoid date- and time-related confusion.
Tropic of Cancer: The imaginary line located at 23°30′ north of the equator. The Sun is directly overhead the Tropic of Cancer on the summer solstice in the Northern Hemisphere (June 20 or 21). It marks the northernmost point of the tropics, which falls between the Tropic of Cancer and the Tropic of Capricorn.
Tropic of Capricorn: The imaginary line located at 23°30′ south. The Sun is directly overhead the Tropic of Capricorn on the summer solstice in the Southern Hemisphere (Dec. 20 or 21). It marks the southernmost point of the tropics.
Arctic Circle: A line of latitude located at 66°30′ north, delineating the Northern Frigid Zone of the Earth.
Antarctic Circle: A line of latitude located at 66°30′ south, delineating the Southern Frigid Zone of the Earth.
Longest river on Earth: Nile 4,160 miles (6,695 km)
Largest lake on Earth: Caspian Sea 143,243 sq miles (371,000 sq km)
Highest point on Earth: Mt. Everest 29,035 ft (8,850 m)
Lowest point on Earth: Dead Sea –1,312 ft (–400 m)
Largest ocean on Earth: Pacific Ocean
Largest desert on Earth: Sahara 3,263,400 sq miles (9,065,000 sq km)
Largest island on Earth: Greenland 836,327 sq miles (2,166,086 sq km)
Coldest place on Earth: Ulan Bator, Mongolia –26°F (–32°C)
Hottest place on Earth: Baghdad, Iraq 110°F (43°C), July/August
Wettest place on Earth (by annual rainfall): Liberia, 202 in (514 cm) of rain per year
Driest place on Earth (by annual rainfall): Egypt, 11°8 in (2.9 cm) of rain per year
Number of nations on Earth: 193
Largest country on Earth: Russian Federation 6,592,800 sq miles (17,075,400 sq km)
Smallest country on Earth: Vatican City 0.17 sq miles (0.44 sq km)
Longest border on Earth: US–Canada 5,526 miles (8,893 km)
Country with most neighbors on Earth: China (14), Russia (14)
Oldest country on Earth: Denmark, AD 950
Youngest country on Earth: East Timor, 2002
Number of people on Earth: Six billion
Top five biggest cities and populations: Tokyo, Japan; New York, NY; Seoul, South Korea; Mexico City, Mexico; and São Paulo, Brazil. (All have over 20 million people.)
Country with smallest population: Vatican City, 900
Most densely populated country: Monaco 42,649 people per sq mile (16,404 people per sq km)
Least densely populated country: Mongolia 4 people per sq mile (2 people per sq km)
Country with highest birth rate: Niger 55 per 1,000 population
Country with lowest birth rate: Hong Kong/Macao (China) 7 per 1,000 population
Country with highest death rate: Sierra Leone 25 per 1,000 population
Country with lowest death rate: United Arab Emirates 2 per 1,000 population
Country with the highest life expectancy: Japan (81)
Country with the lowest life expectancy: Sierra Leone (39)
Richest country (highest GNP*): United States $9,602 billion
Poorest country (lowest GNP*): Tuvalu US$3 million
Map projections: Distorted representations of the relative locations on Earth that allow for two-dimensional map making. There are many types of projections, the most famous being the Mercator projection, which shows the far northern and southern areas as much larger than they are.
Pangea: The most recent single, unified “supercontinent” to have preceded the current continental forms on Earth
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